Organic peroxides

ABSTRACT

This invention discloses a process of preparing organic peroxides, by reacting a hydroperoxide having the general formula R-O-O-H with an Alpha , Beta -unsaturated ketone. The Alpha , Beta -unsaturated ketone may have a straight chain structure or a cyclic structure. Reaction takes place at a temperature from about 0*C.-80*C. in the presence of an acidic catalyst. The mole ratios of the components may vary from about 10:1 to 1:10.

United States Patent Chang et al.

[ Sept. 23, 1975 ORGANIC PERoxIDias Inventors: Yun Ger Chang; Philip S. Bailey,

both of Austin, Tex.

Reichhold Chemicals, Inc., White Plains, NY.

Filed: Dec. 19, 1974 Appl. No.: 534,481

Related US. Application Data Division of Ser. No. 461,969, April 18, 1974, which is a division of Ser. No. 310.560, Nov. 29, 1972, Pat. No. 3,842,129, which is a division of Ser. No. 170,621, Aug. 10, 1971, Pat. No. 3,775,454, which is a division of Ser. No. 754,472, Aug. 21, 1968, abandoned.

Assignee:

US. Cl...... 260/610 R; 260/586 R; 260/593 R;

260/89.3; 260/89.5 A; 260/94.9; 252/426 Int. Cl. C07C 179/06 Field of Search 260/610 R, 610 A, 754,

References Cited FOREIGN PATENTS OR APPLlCATlONS 954,361 4/1964 United Kingdom 260/610 R Primary Examiner.lames O. Thomas, Jr. Assistant ExaminerW. B. Lone [57] ABSTRACT 1 Claim, N0 Drawings ORGANIC PEROXIDES This is a division of my prior application, Ser. No. 461,969, filed Apr. 18, 1974, which is a division ofiSer.

No. 310,560, filed Nov. 29, 197-2, now U.S.- Pat. No.

3,842,129, which in turn is a division of Ser. No. 170,621, filed Aug. 10, 1971, now. US. Pat. '.No.

3,755,454, which in turn is a division of an earlier'apwherein, R is either an alkyl or an aralkyl group; R R and R are the same or different members of the group consisting of hydrogen, alkyl, aralkyl, cycloalkyl, alkenyl, cycloalkenyl, aryl, alkaryl groups; R is a member of the group consisting of alkyl, aralkyl, cycloalkyl, aryl, alkaryl, vinyl and substituted vinyl groups.

Some of these peroxides may be shown by one of the following two formulas: I

. A, R I

and

wherein, R, R, and R; have the same-meanings'as mention ed in the preceding paragraph; A- is a hydrocarbon group containing two to three-carbonatoms in the main chain, of which one terminal carbon atomconnects with the carbonyl group and theother with the beta carbon atom of the a,/3-unsaturated ketones to form a ring, and may be an aliphatic, cycloaliphatic, substi! tut'ed aliphatic, aromatic or substituted aromatic group; and B is a hydrocarbon group containing three to five carbon atoms in the main chain which forms a ring with the a,B-unsaturated system by connecting the carbonyl group with one of. its terminalcarbon atoms and the alpha carbon atom withthe other. and maybe an aliphatic, cycloaliphatic or. substituted aliphatic group.

It has been known for a long time that a,B-unsaturated carbonyl compounds could, be converted into the corresponding epoxides by treatment with hydrogen peroxide in a basic medium. Similarly, was reported in-..the :literature that hydroperoxides could convert B-unsaturated;carbonyl compounds into the corresponding epoxides in the presence of a base. Harman,

US, Pat. No. 2,508,256 (1950),;reported thataddition of hydroperoxide to .an:a,B-unsaturated system con- ;taining a polar, meta-directing group, conjugate to the multiple bond, in a basic medium, producing a peroxide. The meta-directing groups-include theaCHO,

SO H, S0 CONH COCOOH, CO(alkyl) and the like groupsuLater, Yangand Finnegan, J. Am. Chem. Soc.,

80, 5845 (l958),-found that the base-catalyzed reactions .between hydroperoxides, and; a,B-unsaturated systems gave, instead'of peroxides, ponly the corresponding epoxides, in yields of SO-QO-percent. The reaction involves the addition of an alkyl peroxy anion to the beta carbon of the activated-double bond and the elimination of an alkoxy anion withthe formation of the epoxide. if the intermediateanion combines witha proton before the formation of epoxide occurs,-,a peroxy addition product is formed. ltis apparent that in a basicjmedium, the intermediate anion'does not-have the chance to acquire a proton and, consequently, the final product .is an epoxide. lThezmechanism .of the base-catalyzed reaction can be shown as follows;

wherein-Ris eithetfjanalk yl or anaralkyl group.

' it is an object of the present invention to produce peroxides by the addition of hydroperoxides to a,B-unsaturated ketones.

It is another object of the-present invention to provide some novel peroxides which are highly efficient polymerization initiatorsand cross-linking agents.

It is still another objectlof this invention to provide highly efficient methodsfor the preparation of such polymerization initiators and cross-linking agents.

These and other objects and advantages of the present invention will become more apparent from the following description.

It has been found that these objectives can be attained by reacting a,B-unsaturated ketones with hydroperoxides in the presence of a catalyst. The reaction tate, methyl butyrate; may be used as solvents. In the case where no solvent was used, the addition reaction became somewhat violent, as evidenced by the heat evolved.

In the present invention, the catalyst for the addition reaction of hydroperoxidesto a,B-unsaturated ketones is an acid, such as'sulfuric acid, hydrochloric acid, perchloric acid, nitric acid or phosphoric'acid. The use of acidic catalysts in the'addition reaction is very significant, since it leads to the formation of peroxides as the final addition products, without producing epoxides. The amount of the catalyst used for the addition reaction may vary from a trace to about 30 percent, based on the total weight of the reactants described below. Usually, the amount ranging from about 5 to about 15 percent, based on the'total weight of the reactants, is preferred.

In the reactions of the present invention, the mole ratio of a,B-unsat'urated ketone to hydroperoxide may vary widely, for example, from about :1 to 1:10. The

preferred mole ratio of a,B-unsaturated ketone to hydroperoxide is about 1:1 to 1:2.

The reaction temperature of this invention may range from about 0C. to about 80C. However, the preferred reaction temperature isin the range of about 25C. to about 35C., on account of the outstanding results obtained therefrom. At relatively high temperatures, some side-reactions'could take place. For example, when m'esityl oxide was reacted with t-butyl hydroperoxide at 50C. in the presence of sulfuric acid, the product was a mixture of about 50% of di-t-butyl peroxide and about 50% of the desired addition product.

In many cases, the active oxygen contents of the new peroxides of the present invention, as determined by the hydriodic acid-sodium thiosulfate titration method, were lower than the theoretical values. This is probably due to failure of the analytical method in the case of this particular type of peroxide.

The hydroperoxides employed as reactants in this invention may be represented by the general formula ROOH wherein, R is either an alkyl or an aralkyl group. Preferably, these are tertiary hydroperoxides, such as t-butyl hydroperoxide, t-amyl hydroperoxide and cumene hydroperoxide.

The a,B-unsaturated ketones used in this invention may have a straight chain structure or a cyclic structure. They can be represented by one of the following formulas:

Mesityl Oxide w-o-o-n- When hydrocarbon groups, instead of hydrogen atoms, are attached to the beta olefinic carbon atoms, the reaction between a,B-unsaturated ketones and hydroperoxides does not go further than the addition of hydroperoxide to the olefinic double bond. The carbonyl group does not react with hydroperoxide since the infra-red spectra of the peroxidic addition products show a strong bond due to the non-conjugated carbonyl group. Presumably, the limited reaction is due to steric effects. The hydrocarbon group and the bulky alkylperoxy group attached to the beta carbon atom prevent the hydroperoxide from reacting with the carbonyl group. In case of phorone, not only the carbonyl group but also one of the two carbon-carbon double bonds did not react with'hydroperoxide, presumably due to steric hindrance.

The new peroxides of this invention have been found to provide highly efficient initiators in polymerization reactions, such as the polymerization of styrene, vinyl esters, alkyl methacrylates and the like. These peroxides have also been found to be good cross-linking agents for polyethylene, polypropylene and the like.

Some of the representative preparatory reactions are illustrated by the following equations:

4-t-Butylper0xy-4- methyl-2-pentanone EQUATION (2) i The following examples will illustrate the process of preparing the new peroxides of this invention. It is understood, however, that the examples are for purposes of illustrating the invention and are not intended as limitations thereto.

EXAMPLE 1 Preparation of 4-5-Butylperoxy-4-methy1-2 pentanone.

of solvent under reduced pressure using a water aspirator and a rotating evaporator left a light-brown liquid weighing 23.80 grams. This indicated a yield of 64.40 percent, based on the amount of mesityl oxide used for 50 the reaction. The crude product contained no hydroperoxide shown by lead ;tetra-acetate test, and had a 7.10% active oxygen content. After purification by two .distillations at 55C. and 0.7 mm., the colorless liquid product contained 5.74% active oxygen (theoretically,

55 8.50 percent) determined by hydriodic acid-sodium thiosulfate titration. Other constants obtained for this new peroxide were d 0.9370, 1 1.4288, MR (ca1cd.) 52.64, MR (obsd.) 51.83.

Analysis Calcd. for C A- 0 C, 63.79; H, 10.71;

60 O, 25.50; Molecular weight 188. Found: C, 63.80; H,

10.39; 0, 26.06; Molecular weight 234.

The infra-red spectrum of this compound showed a very strong and sharp band at 1,700 cm due to nonconjugated carbonyl groups, a very strong band at 1,360 cm with a shoulder at 1372 cm due to t-butyl groups and a strong band at 870 cm representing the peroxide groups.

On the basis of the analytical data and the information obtained from the infra-red spectrum, the structure of this new peroxide is assigned as follows.

EXAMPLE 2 The procedure of Example 1 was repeated without using an organic solvent. A cooling bath was employed to keep the reaction temperature at 25C. to 35C. The product was extracted with ether. The ether solution was washed with water and dried over anhydrous magnesium sulfate. The final product was identified as 4-tbutylperoxy-4-methyl-2-pentanone.

EXAMPLE 3 Preparation of 4-t-Amylperoxy-4-methyl-2-pentanone.

In a beaker, 10.4 grams (0.1 mole) of t-amyl hydroperoxide and 14.0 grams (0.1 mole) of 70% sulfuric acid were mixed with 100 ml. of hexane. To the resulting mixture was added 9.8 grams (0.1 mole of mesityl oxide, at room temperature, with stirring. The reaction mixture was stirred at room temperature for-5 hours and then allowed to stand overnight. The organic layer was separated and washed five times with -ml. portions of 5% sodium hydroxide solution and twice with water. Finally, it was dried over anhydrous magnesium sulfate. Filtration and removal of solvent under reduced pressure gave a liquid peroxidic product. It was identified as the addition product, 4-t-amylperoxy-4- methyl-2-pentanone.

EXAMPLE 4 Preparation of 4-Cumy1peroxy-4-methyl-2-pentanone.

' To 100 ml. of hexane were added 15.2 grams (0.1 mole) of cumene hydroperoxide and 14.0 grams(0.l mole) of 70% sulfuric acid. To the resulting mixture was added 9.8grams (0.1 mole) of mesityl oxide, at room temperature, with agitation. The reaction mixture was stirred, at room temperature, for five hours andthen allowed to stand overnight. The organic layer was separated and washed five times with l0-ml. portions of 5% sodium hydroxide solution and twice with water. After being dried over anhydrous magnesium sulfate, the solvent was removed under reduced pressure. A liquid was obtained and identified as the 'addition product, 4-cumylperoxy-4-methyl-2-pentanone.

EXAMPLE 5 7 Preparation of 6-t-Butylperoxy-2,6-dimethyl-2-hepten-4-one.

In a 500-ml. round-bottom flask, 25.0 grams (0.25 mole) of 90% t-butyl hydroperoxide, 14.0 grams (0.1 mole) of 70% sulfuric acid and 200 ml. of hexane were mixed together. To the resulting mixture was added 9.4

grams (0.068 mole) of phorone. at room temperature, with stirring. The reaction mixture was stirred at room temperature for twenty-four hours and at 50C. for 24 hours longer. The mixture was diluted with 30 ml. of water. The organic layer was separated, washed 10 times with 10-ml. portions of 5% potassium hydroxide solution and three times with 20-m'l. portions of water, and finally dried over anhydrous magnesium sulfate. Filtration and removal of solvent under reduced pressure left a brown liquid weighing 16.0 grams, indicating a 100 percent yield based on the amount of phorone used for the reaction. The crude product contained no hydroperoxide shown by lead tetra-acetate test, and had a 7.81% active oxygen content determined by hydriodic acid-sodium thiosulfate method. After purification by distillations at 7879C. and 1.5.-mm., the pale yellow liquid contained 6.40% active oxygen (theoretically 7.01%), and had d 0.9950, 11 14494.

Analysis. Calcd. for C H O C, 68.39; H, 10.59; 0, 21.02; Molecular weight 228. Found. C, 67.64; H, 10.29; 0, 21.85; Molecular weight 240. I

The infra-red spectrum of this compound showed a band at 1,672 cm due to conjugated carbonyl groups, a strong band at 1,600 cm due to C=CH- groups, a strong band at 1,360 cm with a shoulder at 1.373 cm indicating t-butyl groups, and a strong band at 864 cm representing peroxide groups.

Based on these data, this new compound is the peroxidic addition product having the following structure.

CH CH EXAMPLE 6 Preparation of 6-t-Amylperoxy-2,6-dimethyl-2-hepten-4-one.

To a mixture of 4.86 grams (0.045 mole) of t-amyl hydroperoxide,'4.20 grams (0.03 mole) of sulfuric acid and 50 ml. of hexane, was added 4.14 grams (0.03 mole) of phorone, at room temperature with agitation. The reaction mixture was stirred at 40."50C. for 48 hours, and then diluted with 10 ml. of water. The organic layer was separated, washed 10 times with 5-ml. portions of 5% sodium hydroxide solution and three times with l0-ml.portions of water, and finally dried over anhydrous magnesium sulfate. Filtration and removal of low-boiling materials under reduced pressure gave a light-brown liquid, identified as the-addition product 6-teamylperoxy-2,6-dimethyl-2-hepten-4-one.

' EXAMPLE 7 p 1 Preparation -of 6-Cumylperoxy-2,6-dimethyl-2-hepten-4-one.

- To'a mixture "of 6.84 g'rams 0.045 mole) of cu mene hydroperoxide, 4.20 grams (0.03'mole) of 70% sulfuric acid and 50 ml.'ofhexane, was added 4.14 grams (0.03 mole) of phorone, at room temperature;"with stirring. The reaction mixture was stirred at 4050C. for 48 hours. It was diluted'with 10 ml. of water. The organic layer was separated, washed ten times with -ml. portions of 5% sodium hydroxide solution and three times with lO-ml. portions'of water, and then dried over anhydrous magnesium sulfate. Filtration and removal of low-boiling materials under reduced pressure left a light-brown liquid, identified as the addition product 6cumylperoxy-2,6-dimethyl-2-hepten-4-one.

EXAMPLE 8 Preparation of 3-t-Butylperoxy-3 ,5 ,5 -trimet hylcyclohexanone.

To a mixture of 30.0 grams (0.3 mole) of 90% t-butyl hydroperoxide, 14.0 grams (0.1 mole) of 70% sulfuric acid and 200 ml. of hexane, was added 13.8 grams (0.1 mole) of isophorone, at room temperature, with agitation. The reaction mixture was stirred, at room temperature, for 5 hours and then allowed to stand overnight. The organic layer was separated, washed twice with 50- ml. portions of saturated sodium bicarbonate solution and twice with water, and finally dried over anhydrous magnesium sulfate. Filtration and removal of lowboiling materials under reduced pressure gave a lightbrown liquid, weighing 23.4 grams. The product was purified by five distillations at 65-67C. and 1.0 mm. The purified liquid contained no hydroperoxide and had a refractive index 17 14450. The infra-red spectrum of this compound showed a strong band at 1,725 cm due to non-conjugated cyclic carbonyl groups; a strong band at 1,370 cm due to C-Cl-l and C(CH groups; and a strong band at 878 cm due to peroxide groups. The active oxygen content of this compound determined by hydriodic acid-sodium thiosulfate titration method seemed higher than the theoretical value.

According to these data, it is reasonable to assign the following structure for this compound.

EXAMPLE 9 The preparation described in Example 8 was carried out without using organic solvent. The isophorone was mixed with the t-butyl hydroperoxide. To the resulting mixture was slowly added the sulfuric acid at room temperature. The reaction mixture was stirred for thirty hours while the temperature was kept at 2530C., using a cold water bath. The reaction mixture was diluted with water. The organic layer was separated, washed with sodium bicarbonate solution and with water, and finally dried over anhydrous magnesium sulfate. The final product was identified as 3-tbutylperoxy-3,5,5-trimethyl-cyclohexanone.

EXAMPLE 10 Preparation of 3-5-Amylperoxy-3 ,5 ,5-trimethylcyclohexanone.

To a mixture of 6.24 grams (0.06 mole) of t-amyl hydroperoxide, 4.20 grams (0.03 mole) of 70% sulfuric acid and ml. of hexane, was added 4.14 grams (0.03 mole) of isophorone, at room temperature, with stirring. The reaction mixture was stirred at room temperature for five hours, and then allowed to stand overnight. The organic layer was separated. washed twice with l0-ml. portions of saturated sodium bicarbonate solution and twice with lO-ml. portions of water, and finally dried over anhydrous magnesium sulfate. Filtration and removal of low-boiling materials under reduced pressure left a liquid product, identified as the addition product, 3-t-amylperoxy-3, 5,5-trimethylcyclohexanone.

EXAMPLE 1 1 Preparation of 3-Cumylperoxy-3,5 ,5 -trimethylcyclohexanone.

To a mixture of 9.12 grams (0.06 mole) of cumene hydroperoxide, 4.20 grams (0.03 mole) of sulfuric acid, and 40 ml. of hexane was added 4.14 grams (0.03 mole) of isophorone, at room temperature, with agitation. The reaction mixture was stirred at room temperature for 5 hours, and then allowed to stand overnight. The organic layer was separated. It was washed twice with 10-ml. portions of saturated sodium bicarbonate solution and twice with water, and finally dried over anhydrous magnesium sulfate. Filtration and removal of low-boiling materials under reduced pressure gave a liquid product, identified as the addition product, 3- cumylperoxy-3,5,5-trimethylcyclohexanone.

EXAMPLE 12 Preparation of 2-( l-t-butylperoxyl -methylethyl )-5-methylcyclohexanone.

To a mixture of 6.0 grams (0.06 mole) of t-butyl hydroperoxide, 4.20 grams (0.03 mole) of 70% sulfuric acid, and 40 ml. of hexane, was added 4.56 grams (0.03 mole) of pulegone, at room temperature, with stirring. The reaction mixture was stirred, at room temperature,

for five hours and then allowed to stand overnight. The

organic layer was separated, washed twice with 20-ml. portions of saturated sodium bicarbonate solution and twice with 20-ml. portions of water, and finally dried over anhydrous magnesium sulfate. Filtration and removal of low-boiling materials under reduced pressure left a liquid product, identified as the addition product, having the following structure.

The invention in its broader aspects is not limited to the specific steps, methods, and compositions described, but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What is claimed is:

1. An organic peroxide namely 3-cumylperoxy-3, 5,

S-trimethylcyclohexanone. 

1. AN ORGANIC PEROXIDE NAMELY 3-CUMYLPEROXY-3, 5, 5TRIMETHYLCYCLOHEXANONE. 